With the advancement of semiconductor manufacturing technology, it is now possible to fabricate electro-mechanical components on semiconductor wafers—this new area of technology is often referred to as micro-electro-mechanical systems (MEMS).
Presently, MEMS components are typically fabricated using two conventional approaches. The first conventional approach uses only one wafer, wherein the electro-mechanical components and the electronic circuit components are fabricated on the same wafer. In this regard, the electro-mechanical components are fabricated using post integrated circuit (IC) processes.
A typical problem faced when using this first approach is that active components (such as electronic, optical or optical-electronic (EO)) are usually fabricated within thin wafers (typically less than 1 micrometer (μm)), whereas MEMS components (such as mirrors) are usually fabricated within thick structured wafers (typically larger than 10 μm). As such, it is difficult to align the active components and the MEMS components on the same plane.
The second conventional approach uses two wafers, wherein the MEMS components and the active components may be fabricated on different wafers. Subsequently, the two wafers are integrated together by a wafer-to-wafer bonding process.
In this second approach where two wafers are used, the x-axis and y-axis alignments between the two wafers depend largely on the accuracy of the wafer-to-wafer bonding process. This means that a low accuracy of the wafer-to-wafer bonding process would result in a poor alignment between the active components and the MEMS components on the two wafers. Further, since the components on a first wafer and the components on a second wafer are on different planes, it is difficult to achieve accurate alignment along the x-axis, the y-axis and the z-axis as well.
A solution to overcome the alignment related problems involved with the fabrication of MEMS components on semiconductor wafers is the wafer arrangement and the method for manufacturing the wafer arrangement, as defined in the respective independent claims of the present application.